As a data output apparatus of word processors, personal computers, facsimiles and so forth, printers capable of printing desired information such as texts and images on a sheet-type printing medium, e.g., paper, film and the like, are widely utilized.
Although various printing methods are available for such printers, recently an inkjet printing method has particularly attracted attention because of its capability to perform non-contact printing on a printing medium such as paper, ease of color printing, and low noise. Moreover, for a configuration of such a printer, in general a serial printing method is widely adopted because of its low cost and ease of downsizing. According to the serial printing method, a printhead discharging ink in accordance with desired printing data is attached to a carriage and printing is performed by reciprocally scanning the carriage in a direction crossing the conveyance direction of the printing medium (e.g., paper).
Conventionally, there is known a printing apparatus (a printer) that, in order to perform printing by scanning a carriage mounted with a printhead on a printing medium, divides a printing area in a scanning direction of the printhead into plural areas and has a buffer for storing printing data in units of the divided area.
Such a printing apparatus includes a write control unit that, in storing the printing data in units of the divided area in the buffer, controls write address information of printing data in units of area for each color data on the basis of information for switching a storing area of data for each color data, a result of comparison of a remaining buffer capacity available for storage and an updated amount of write addresses.
The printing apparatus also includes a read control unit that controls, for each color data, read address information for reading the printing data stored in the buffer and printing data generating means that generates printing data in units of the divided area in accordance with the printing data that is read on the basis of the read address information.
In the conventional printing apparatus constituted as described above, it is necessary to perform adjustment for a printing location in the scanning direction (registration adjustment) before actually performing printing. Such registration adjustment is executed on a host computer (a printer driver) side (Japanese Patent Application Laid-Open No. 2003-305895) or executed on the printing apparatus side.
Printing data transferred to the printing apparatus is generally represented by one bit (binary) for representing printing or non-printing. However, usually, a data processing unit of the host computer is set to 16 bits or 32 bits. Thus, it is inefficient to process data of one bit such as the printing data with the host computer and the processing takes time.
Therefore, when the registration adjustment is performed using the host computer (the printer driver), if an amount of printing data increases, the host computer takes time in generating printing data. As a result, an actual speed from instruction of printing until execution of the printing in the printing apparatus falls.
On the other hand, when the registration adjustment is performed using the printing apparatus, a buffer size corresponding to a width of the registration adjustment is always required. Thus, if the width of the registration adjustment increases, the buffer size required in the printing apparatus increases. As a result, cost for hardware increases.